/Engine/Source/Runtime/Core/Public/Misc/FileHelper.h
Checks to see if a filename is valid for saving. A filename must be under FPlatformMisc::GetMaxPathLength() to be saved
static bool IsFilenameValidForSaving ( const [FString](API\Runtime\Core\Containers\FString) & Filename, [FText](API\Runtime\Core\Internationalization\FText) & OutError )